期刊文献+
共找到2,025篇文章
< 1 2 102 >
每页显示 20 50 100
Stochastic Air Traffic Flow Management for Demand and Capacity Balancing Under Capacity Uncertainty
1
作者 CHEN Yunxiang XU Yan ZHAO Yifei 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第5期656-674,共19页
This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)f... This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)framework.Further with previous study,the uncertainty in capacity is considered as a non-negligible issue regarding multiple reasons,like the impact of weather,the strike of air traffic controllers(ATCOs),the military use of airspace and the spatiotemporal distribution of nonscheduled flights,etc.These recessive factors affect the outcome of traffic flow optimization.In this research,the focus is placed on the impact of sector capacity uncertainty on demand and capacity balancing(DCB)optimization and ATFM,and multiple options,such as delay assignment and rerouting,are intended for regulating the traffic flow.A scenario optimization method for sector capacity in the presence of uncertainties is used to find the approximately optimal solution.The results show that the proposed approach can achieve better demand and capacity balancing and determine perfect integer solutions to ATFM problems,solving large-scale instances(24 h on seven capacity scenarios,with 6255 flights and 8949 trajectories)in 5-15 min.To the best of our knowledge,our experiment is the first to tackle large-scale instances of stochastic ATFM problems within the collaborative ATFM framework. 展开更多
关键词 air traffic flow management demand and capacity balancing flight delays sector capacity uncertainty ground delay programs probabilistic scenario trees
下载PDF
Enlarging Zn deposition space via regulating Sn-induced effective interface for high areal capacity zinc-based flow battery
2
作者 Yuning Sun Siyu Zhang +5 位作者 Qiming Zhang Lantong Cui Pengfei Wang Yanbin Yin Qian Wang Qinzhi Lai 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第11期579-586,I0012,共9页
Zinc-based flow batteries(ZFBs)have aroused great favor in large-scale energy storage due to the high security and low cost.However,the low areal capacity arising from the limited space for Zn plating hinders the furt... Zinc-based flow batteries(ZFBs)have aroused great favor in large-scale energy storage due to the high security and low cost.However,the low areal capacity arising from the limited space for Zn plating hinders the further development.Herein,a novel carbon felt-Sn-carbon felt sandwich host(CSCH)is designed and constructed.Benefiting from the strong chemical absorption and the dehydration effect on Zn(H_(2)O)_(6)^(2+),the Sn activation layer in the CSCH demonstrates the lowest comprehensive resistance for Zn deposition.Thus,Zn is induced to nucleate preferentially on the Sn activation layer,and grows towards the membrane,regulating the spatial distribution of Zn electrochemical deposits,which remarkably improves the areal capacity and cyclic stability of Zn anode.Consequently,the zinc-bromine flow batteries equipped with CSCH electrodes can achieve the ultra-high areal capacity of 120 mA h cm^(-2)at 80 mA cm^(-2),and run stably for 140 h with average energy efficiency of 80.3%in the extreme condition(80 mA cm^(-2),80 mA h cm^(-2)).This innovative work will inspire future advanced designs for high areal capacity electrodes in ZFBs. 展开更多
关键词 Zinc-based flow batteries High areal capacity Sn-induced deposition Zn deposition depth
下载PDF
Capacity of Mixed Traffic Flow Crossing Multi-Major-Lanes 被引量:2
3
作者 李文权 王炜 周刚 《Journal of Southeast University(English Edition)》 EI CAS 2000年第2期100-104,共5页
Based on the gap acceptance theory, the mixed traffic flow composed of r representative types of vehicles 1, 2,…, r vehicles is analyzed with probability theory. Capacity model of the minor mixed traffic flow ... Based on the gap acceptance theory, the mixed traffic flow composed of r representative types of vehicles 1, 2,…, r vehicles is analyzed with probability theory. Capacity model of the minor mixed traffic flow crossing m major lanes with M3 distributed headway on the unsignalized intersection is set up, and it is an extension of capacity model for one minor lane vehicle type crossing one major lane traffic flow. 展开更多
关键词 M3 distribution HEADWAY gap acceptance traffic flow capacity
下载PDF
Pore throat structure heterogeneity and its effect on gas-phase seepage capacity in tight sandstone reservoirs:A case study from the Triassic Yanchang Formation,Ordos Basin 被引量:1
4
作者 Yu-Bin Yang Wen-Lian Xiao +8 位作者 Ling-Li Zheng Qi-Hong Lei Chao-Zhong Qin You-An He Shuai-Shuai Liu Min Li Yong-Ming Li Jin-Zhou Zhao Meng Chen 《Petroleum Science》 SCIE EI CSCD 2023年第5期2892-2907,共16页
The microscopic heterogeneity of pore-throat structures in tight sandstone is a crucial parameter for understanding the transport mechanism of fluid flow.In this work,we firstly developed the new procedure to characte... The microscopic heterogeneity of pore-throat structures in tight sandstone is a crucial parameter for understanding the transport mechanism of fluid flow.In this work,we firstly developed the new procedure to characterize the pore size distribution(PSD)and throat size distribution(TSD)by combining the nuclear magnetic resonance(NMR),cast thin section(CTS),and constant-rate mercury injection(CRMI)tests,and used the permeability estimated model to verify the full-scale PSD and TSD.Then,we respectively analyzed the fractal feature of the pore and throat,and characterized the heterogeneity of pores and throats.Finally,we elaborated the effect of the pore and throat heterogeneity on the gas-phase seepage capacity base on the analysis of the simple capillary tube model and gas-flooding experiment.The results showed that(1)The PSD and TSD of the tight sandstone sample ranged from 0.01 to 10 mm and from 0.1 to 57 mm,respectively,mainly contributed by the micropores and mesopores.Meanwhile,the permeability estimated by the PSD and TSD was consistent with the experimental permeability,and relative error was lower than 8%.(2)The PSD and TSD exhibited multifractal characteristics,and singularity strength range,Δα,could be used as the indicator for characterizing the heterogeneity of pore and throat.Furthermore,the throat of the sample showed stronger heterogeneity than that the pore.(3)The throats played an important role for the fluid transport in the tight sandstone,and the effect of the throat heterogeneity on the gas-phase seepage capacity was different under the lower and higher injection pressure.The macropores and micropores maybe respectively become the preferential migration pathways at the lower and higher injection pressure.In the end,the identification plate was established in our paper,and could be described the relationship among the throat heterogeneity,injection pressure,permeability and flow path of the gas phase in the tight sandstone. 展开更多
关键词 Tight sandstone Pore size distribution(PSD) Throat size distribution(TSD) Pore and throat heterogeneity Gas-phase flow capacity Nuclear magnetic resonance(NMR) Constant-rate mercury injection(CRMI)
下载PDF
Influences of nonassociated flow rules on seismic bearing capacity factors of strip footing on soil slope by energy dissipation method 被引量:14
5
作者 杨小礼 郭乃正 +1 位作者 赵炼恒 邹金锋 《Journal of Central South University of Technology》 EI 2007年第6期842-847,共6页
Seismic bearing capacity factors of a strip footing placed on soil slope were determined with both associated and nonassociated flow rules. Quasi-static representation of earthquake effects using a seismic coefficient... Seismic bearing capacity factors of a strip footing placed on soil slope were determined with both associated and nonassociated flow rules. Quasi-static representation of earthquake effects using a seismic coefficient concept was adopted for seismic bearing capacity calculations. A multi-wedge translational failure mechanism was used to obtain the seismic bearing capacity factors for different seismic coefficients and various inclined angles. Employing the associated flow rule, numerical results were compared with the published solutions. For bearing capacity factors related to cohesion and equivalent surcharge load, the maximum difference approximates 0.1%. However, the difference of bearing capacity factor related to unit weight is larger. With the two flow rules, the seismic bearing capacity factors were presented in the form of design charts for practical use. The results show that seismic bearing capacity factors related to the cohesion, the equivalent surcharge load and the unit weight increase greatly as the dilatancy angle increases, and that the nonassociated flow rule has important influences on the seismic bearing capacity. 展开更多
关键词 nonassociated flow rule seismic bearing capacity factor EARTHQUAKE
下载PDF
A Genetic Algorithm to Solve Capacity Assignment Problem in a Flow Network 被引量:6
6
作者 Ahmed Y.Hamed Monagi H.Alkinani M.R.Hassan 《Computers, Materials & Continua》 SCIE EI 2020年第9期1579-1586,共8页
Computer networks and power transmission networks are treated as capacitated flow networks.A capacitated flow network may partially fail due to maintenance.Therefore,the capacity of each edge should be optimally assig... Computer networks and power transmission networks are treated as capacitated flow networks.A capacitated flow network may partially fail due to maintenance.Therefore,the capacity of each edge should be optimally assigned to face critical situations-i.e.,to keep the network functioning normally in the case of failure at one or more edges.The robust design problem(RDP)in a capacitated flow network is to search for the minimum capacity assignment of each edge such that the network still survived even under the edge’s failure.The RDP is known as NP-hard.Thus,capacity assignment problem subject to system reliability and total capacity constraints is studied in this paper.The problem is formulated mathematically,and a genetic algorithm is proposed to determine the optimal solution.The optimal solution found by the proposed algorithm is characterized by maximum reliability and minimum total capacity.Some numerical examples are presented to illustrate the efficiency of the proposed approach. 展开更多
关键词 flow network capacity assignment network reliability genetic algorithms
下载PDF
CFD Prediction of Mean Flow Field and Impeller Capacity for Pitched Blade Turbine 被引量:2
7
作者 乔胜超 王日杰 +1 位作者 杨晓霞 闫越飞 《Transactions of Tianjin University》 EI CAS 2015年第3期250-258,共9页
This work focused on exploring a computational fluid dynamics(CFD)method to predict the macromixing characteristics including the mean flow field and impeller capacity for a 45° down-pumping pitched blade turbine... This work focused on exploring a computational fluid dynamics(CFD)method to predict the macromixing characteristics including the mean flow field and impeller capacity for a 45° down-pumping pitched blade turbine(PBT)in stirred tanks. Firstly, the three typical mean flow fields were investigated by virtue of three components of liquid velocity. Then the effects of impeller diameter(D)and off-bottom clearance(C)on both the mean flow field and three global macro-mixing parameters concerning impeller capacity were studied in detail. The changes of flow patterns with increasing C/D were predicted from these effects. The simulation results are consistent with the experimental results in published literature. 展开更多
关键词 CFD simulation PBT stirred tank flow field pumping capacity
下载PDF
An Algorithm for Traffic Equilibrium Flow with Capacity Constraints of Arcs 被引量:1
8
作者 Zhi Lin 《Journal of Transportation Technologies》 2015年第4期240-246,共7页
In the traffic equilibrium problem, we introduce capacity constraints of arcs, extend Beckmann’s formula to include these constraints, and give an algorithm for traffic equilibrium flows with capacity constraints on ... In the traffic equilibrium problem, we introduce capacity constraints of arcs, extend Beckmann’s formula to include these constraints, and give an algorithm for traffic equilibrium flows with capacity constraints on arcs. Using an example, we illustrate the application of the algorithm and show that Beckmann’s formula is a sufficient condition only, not a necessary condition, for traffic equilibrium with capacity constraints of arcs. 展开更多
关键词 The Traffic EQUILIBRIUM Problem with capacity Constraints of ARCS EQUILIBRIUM flow ALGORITHM capacity of ARC Saturated PATH
下载PDF
Mixed Traffic Flow Capacity of More Major Lanes Unsignalized Intersection 被引量:1
9
作者 TIAN Xin-xian 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第3期462-469,共8页
Highway capacity is defined as maximum volume of traffic flow through the particular highway section under given traffic conditions, road conditions and so on. Highway construction and management is judged by capacity... Highway capacity is defined as maximum volume of traffic flow through the particular highway section under given traffic conditions, road conditions and so on. Highway construction and management is judged by capacity standard. The reasonable scale and time of highway construction, rational network structure and optimal management mode of highway network can be determined by analyzing the fitness between capacity and traffic volume. All over the world, highway capacity is studied to different extent in different country. Based on the gap acceptance theory, the mixed traffic flow composed of two representative vehicle types heavy and light vehicles is analyzed with probability theory. Capacity model of the minor mixed traffic flows crossing m major lanes, on which the traffic flows fix in with M3 distributed headway, on the unsignalized intersection is set up, and it is an extension of minor lane capacity theory for one vehicle-type and one major-lane traffic flow. 展开更多
关键词 HEADWAY gap acceptance mixed traffic flow highway capacity
下载PDF
The Clinical Role of Changes of Maximum Expiratory Flow at 25%and 50%of Vital Capacity before and after Bronchodilator Reversibility Test in Diagnosing Asthma
10
作者 Xu-xuc GUO Xiao-fan LIU +7 位作者 Ai-ling WANG Qian-hui CHEN Shuo CHEN Ni-shan DENG Rui-yun LI Xu-hong DING Su ping HU Han-xiang NIE 《Current Medical Science》 SCIE CAS 2020年第4期677-682,共6页
Summary:Changes of maximum expiratory flow at 25%and 50%of vital capacity(MEF2s and MEFso,respectively),and predominant parameters indicating small airways function in asthmatics before and after bronchodilator(BD)rev... Summary:Changes of maximum expiratory flow at 25%and 50%of vital capacity(MEF2s and MEFso,respectively),and predominant parameters indicating small airways function in asthmatics before and after bronchodilator(BD)reversibility test have been less interpreted.Our study aimed to investigate the clinical role of changes of MEF2s and MEFso before and after BD reversibility test in diagnosing asthma.Forced expiratory volume in the first second(FEV),MEF2s,and MEFso were measured before and after BD reversibility test in 207 asthmatic patients using standard process.Forty healthy individuals were enrolled as controls.Receiver operating characteristic(ROC)curve was used to assess the diagnostic accuracy of reversibility of MEF2s and MEFgo before and after BD reversibility test(OMEF 2s%and AMEF so%,respectively)in diagnosing asthma.Among these functional criteria,AMEF2;%and 0MEFs%≥25%performed the best diagnostic performance.The sensitivity,specificity,and accuracy of AMEF 25%≥25%as an objcctive diagnostic test for asthma were 63.29%,87.50%,and 67.21%,and of AMEFs0%≥25%were 79.23%,85.00%,and 80.16%,respectively.The area under the ROC curve of the indicators was 0.8203 and 0.9104,respectively.By contrast,an increase in FEV≥12%and 200 mL demonstrated a sensitivity of 62.32%,specificity of 82.50%,and accuracy of 65.59%in diagnosing asthma.The changes of MEF2s and MEFso before and after BD reversibility test may be of additional value in the clinical diagnosis of asthma,with cutoff values of 25%being the most. 展开更多
关键词 ASTHMA bronchodilator reversibility test maximum expiratory flow at 25%of vital capacity maximum expiratory flow at 50%of vital capacity
下载PDF
Numerical Study on Hydraulic Characteristics and Discharge Capacity of Modified Piano Key Weir with Various Inlet/Outlet Width Ratio
11
作者 Ilan Ich Genguang Zhang +2 位作者 Anbin Li Vinhteang Kaing Ty Sok 《World Journal of Engineering and Technology》 2023年第1期113-135,共23页
A modified piano key weir with a rounded nose and a parapet wall (MPKW) can improve the discharge capacity significantly compared to a standard piano key weir. However, the optimum of the inlet/outlet width ratio (Wi/... A modified piano key weir with a rounded nose and a parapet wall (MPKW) can improve the discharge capacity significantly compared to a standard piano key weir. However, the optimum of the inlet/outlet width ratio (Wi/Wo) on the discharge efficiency of MPKW is still not investigated numerically. The present work utilized the numerical modeling to investigate and analyze the effects of the inlet/outlet key width ratios on the hydraulic characteristics and discharge capacity of the MPKW. To validate the numerical model with the experimental data, the results indicate that the average relative error is 2.96%, which confirms that the numerical model is fairly well to predictthe specifications of flow over on the MPKW. Numerical simulation results indicated that the discharge capacity of the MPKW can be improved up to 8.5% by optimizing the Wi/Wo ratio ranging from 1.53 to 1.67 even if the other parameters of the MPKW keep unchanged. A big Wi/Wo ratio generally leads to an increase in discharge capacity at low heads and a little effect on the discharge efficiency at high heads. The discharge efficiency of the inlet and outlet crests increases up to 9.6% for high heads, while discharge efficiency of the lateral crest decreases up to 23.5% compared with the reference model. The findings of the study revealed that the intrinsic influencing mechanism of the Wi/Wo ratio on the discharge performance of MPKWs. 展开更多
关键词 Discharge capacity flow-3D Hydraulic Characteristics Numerical Simulation Modified Piano Key Weir Parameter Optimization
下载PDF
Influence of Particles on the Loading Capacity and the Temperature Rise of Water Film in Ultra-high Speed Hybrid Bearing 被引量:3
12
作者 ZHU Aibin LI Pei +2 位作者 ZHANG Yefan CHEN Wei YUAN Xiaoyang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第3期541-548,共8页
Ultra-high speed machining technology enables high efficiency, high precision and high integrity of machined surface. Previous researches of hybrid bearing rarely consider influences of solid particles in lubricant an... Ultra-high speed machining technology enables high efficiency, high precision and high integrity of machined surface. Previous researches of hybrid bearing rarely consider influences of solid particles in lubricant and ultra-high speed of hybrid bearing, which cannot be ignored under the high speed and micro-space conditions of ultra-high speed water-lubricated hybrid bearing. Considering the impact of solid particles in lubricant, turbulence and temperature viscosity effects of lubricant, the influences of particles on pressure distribution, loading capacity and the temperature rise of the lubricant film with four-step-cavity ultra-high speed water-lubricated hybrid bearing are presented in the paper. The results show that loading capacity of the hybrid bearing can be affected by changing the viscosity of the lubricant, and large particles can improve the bearing loading capacity higher. The impact of water film temperature rise produced by solid particles in lubricant is related with particle diameter and minimum film thickness. Compared with the soft particles, hard particles cause the more increasing of water film temperature rise and loading capacity. When the speed of hybrid bearing increases, the impact of solid particles on hybrid bearing becomes increasingly apparent, especially for ultra-high speed water-lubricated hybrid bearing. This research presents influences of solid particles on the loading capacity and the temperature rise of water film in ultra-high speed hybrid bearings, the research conclusions provide a new method to evaluate the influence of solid particles in lubricant of ultra-high speed water-lubricated hybrid bearing, which is important to performance calculation of ultra-high speed hybrid bearings, design of filtration system, and safe operation of ultra-high speed hybrid bearings. 展开更多
关键词 hybrid bearing liquid-solid flow solid particles loading capacity temperature rise
下载PDF
Capacity models on expressway near a bus bay stop with an access 被引量:3
13
作者 张洪宾 孙小端 +1 位作者 贺玉龙 宇仁德 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第8期3239-3246,共8页
To determinate the expressway capacity near a bus bay stop with an access, capacity models on the expressway near a bus stop with an access were developed on the basis of gap acceptance theory and queuing theory. Depe... To determinate the expressway capacity near a bus bay stop with an access, capacity models on the expressway near a bus stop with an access were developed on the basis of gap acceptance theory and queuing theory. Depending on a bus stop position to an entrance or an exit ramp, the capacity models were developed for four cases. Bus bay stops with overflow and bus bay stops without overflow were considered. A comparison of simulation experiment and model calculation was carried out. Results show that the suggested models have high accuracy and reliability, at bus arrival rate below 60 vehicles per hour(veh/h) or vehicle volumes at the entrance and the exit below 200 passenger cars units per hour(pcu/h), and there are no significant difference in the capacities for four cases. When bus arrival rate is above 240 veh/h, the capacities of all four cases will decline rapidly. With berth number increasing, the increasing of the capacities is no obvious for four cases. As the bus arrival rate and vehicle volumes at the entrance and the exit increase, bus stops located downstream of an entrance and upstream of an exit have a remarkably effect on the capacities. The latter case is much heavier than the former. Those results can be used to traffic design and optimization on urban expressway near a bus stop with an access. 展开更多
关键词 capacity public transport entrance and exit traffic flow theory DELAY
下载PDF
Analysis of influencing factors on suction capacity in seabed natural gas hydrate by cutter-suction exploitation 被引量:2
14
作者 XU Hai-liang KONG Wei-yang HU Wen-gang 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第12期2883-2895,共13页
The mathematical and simulation models of working head in the deep-sea working environment were built to analyze the effects of cutter-suction flow,cutter-head rotating speed,cutting depth and suction port position on... The mathematical and simulation models of working head in the deep-sea working environment were built to analyze the effects of cutter-suction flow,cutter-head rotating speed,cutting depth and suction port position on the cutter-suction capacity.The efficiency of the cutter-suction is analyzed based on the analysis of the variation law of the solid-phase volume fraction of the flow field,the variation law of the velocity distribution in the flow field and the distribution law of the solid-phase concentration.The results show that the increase of cutter-suction flow can significantly improve the cutter-suction efficiency when it is less than1000m3/h.However,when it is more than1000m3/h,it is helpless.When the cutter-head rotate speed is within the range of10–25r/min,the cutter-suction efficiency stabilizes at about95%.While the speed is greater than25r/min,the cutter-suction efficiency decreases sharply with the increase of cutter-head rotate speed.With the increase of cutting depth,the cutter-suction efficiency first increases and then remains stable and finally decreases.The cutter-suction efficiency remains at about94%when the suction port position deviation ranges from0°to30°,but it has a sharply reduction when the deviation angle is more than30°. 展开更多
关键词 seabed natural gas hydrate working head solid-liquid two-phase flow cutter-suction capacity influencing factor
下载PDF
Effects of Rigid Vegetation on the Turbulence Characteristics in Sediment-Laden Flows 被引量:1
15
作者 Shengqi Lu Jieren Chen 《Journal of Applied Mathematics and Physics》 2014年第12期1091-1098,共8页
The effects of rigid vegetation on the turbulence characteristics were experimentally studied in the interior water flume. An ADV was used to determine the three dimensional turbulent velocities in clear water flow wi... The effects of rigid vegetation on the turbulence characteristics were experimentally studied in the interior water flume. An ADV was used to determine the three dimensional turbulent velocities in clear water flow without vegetation, sediment-laden flow without vegetation, sediment-laden flow with submerged vegetation and sediment-laden flow with non-submerged vegetation. By experimental and theoretical analysis, the effects of rigid vegetation on the distribution of averaged velocities, turbulence intensities and Reynolds stress were summarized. In sediment-laden flow with submerged vegetation, the averaged stream wise velocities above the top of vegetation fit well with the log distribution low. The three-dimensional turbulence intensities increase from the bottom until they reach the maximum at the top of the vegetation. The method to calculate the shear velocity with the maximum of the Reynolds stress is recommended. In sediment-laden flow with non-submerged vegetation, the turbulence problems cannot be explained by theory of bed shear flow. The average velocities, turbulence intensities and Reynolds stress approximate uniformly distributed along vertical direction. 展开更多
关键词 RIGID VEGETATION TURBULENCE CHARACTERISTICS sediment-laden flow EXPERIMENTAL Study
下载PDF
Evaluation of optimal UPFC allocation for improving transmission capacity 被引量:1
16
作者 Xuhui Shen Hongmei Luo +2 位作者 Wenman Gao Yuyao Feng Nan Feng 《Global Energy Interconnection》 2020年第3期217-226,共10页
A unified power flow controller(UPFC)combines the advantages of various flexible alternating current transmission system(FACTS)devices into a powerful format.Using a 500 kV power grid,this study evaluates the selectio... A unified power flow controller(UPFC)combines the advantages of various flexible alternating current transmission system(FACTS)devices into a powerful format.Using a 500 kV power grid,this study evaluates the selection and use of a UPFC to improve transmission capacity.The"UPFC unit capacity control proportionality coefficient"is introduced to quantify the control effect of the UPFC,and an optimal calculation method for the UPFC capacity is presented.Following the proposal of a UPFC site selection process,the data of an existing power grid is used to conduct simulations.The simulation results show that the UPFC has a strong ability to improve transmission capacity,and its use is greatly advantageous.Additionally,by applying the proposed selection method,the control effect and economic benefits of the UPFC can be comprehensively considered during project site selection.These findings have a guiding significance for UPFC site selection in ultra-high voltage power grids. 展开更多
关键词 Unified power flow controller UPFC unit capacity control proportionality coefficient UHV power grid Transmission capability Optimal capacity calculation UPFC site selection
下载PDF
Bicycle capacity of borrowed-priority merge at unsignalized intersections in China
17
作者 杨小宝 环梅 +1 位作者 四兵锋 高亮 《Journal of Beijing Institute of Technology》 EI CAS 2012年第2期229-233,共5页
To investigate bicyclists' behavior at unsignalized intersections with mixed traffic flow, a bicycle capacity model of borrowed-priority merge was developed by the addition-conflict-flow procedure. Based on the actua... To investigate bicyclists' behavior at unsignalized intersections with mixed traffic flow, a bicycle capacity model of borrowed-priority merge was developed by the addition-conflict-flow procedure. Based on the actual traffic situation, the concept of borrowed priority, in which the majorroad bicycles borrow the priority of major-road cars to enter the intersections when consecutive headway for major-steam cars is lower than the critical gap for minor-road cars, was addressed. Bicycle capacity at a typical unsignalized intersection is derived by the addition-conflict-flow procedure. The proposes model was validated by the empirical investigation. Numerical results show that bicycle capacity at an intersection is the function of major-road and minor-road car streams. Bicycle capacity increases with increasing major-road cars but decreases with increasing minorroad cars. 展开更多
关键词 mixed traffic flow unsignalized intersection bicycle capacity PRIORITY
下载PDF
The Loading Capacity of the Elands River: A Case Study of the Waterval Boven Wastewater Treatment Works, Mpumalanga Province, South Africa
18
作者 Sandile Dlamini Thomas K. Gyedu-Ababio Andrew Slaughter 《Journal of Water Resource and Protection》 2019年第8期1049-1063,共15页
Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the p... Nutrient loads into water resources continues to be a major problem in Southern Africa. This has resulted in significant compromises in the ecological integrity of freshwater resources. The study aimed to assess the pollution load into the Elands River in terms of nitrates and orthophosphates. These variables were compared against the Crocodile Catchment Interim Resource Quality Objectives to determine compliances or non-compliance of the Waterval Boven wastewater treatment plant. Generally upstream nitrate levels did not exceed the ideal limit of 0.5 mg·l-1 as indicated in the 2015 to 2016 samples where values ranged between 0.32 mg·l -1 and 0.27 mg·l-1, respectively. Similarly, observed upstream orthophosphates levels were below the ideal limit of 0.03 mg·l-1. However, downstream values of both nutrients exceeded the respective set limits. The nutrient load contribution from the sewage plant was characterised by a simple point-source model. Patterns of the loads into the river were demonstrated on a load duration curve based on the river which equalled or exceed 0.18 m3/s upstream and 1.31 m3/s downstream at 90% of the time. However, the flows were regarded as significantly low to deal with uncontrolled pollution loads. Most of the observed loads fell below the ideal limit of 0.05 mg·l-1 for nitrates both upstream and downstream of the sewage plant. For orthophosphates, most of the upstream loads were below the tolerable limit of 0.1 mg·l-1 whilst the downstream loads were exceeding the tolerable limits. The higher loads downstream in the river were attributed to the sewage discharge from the Waterval Boven wastewater treatment plant and the low river flows. Hence it could be concluded that river water quality should be interpreted based on the river flow regime in a given season. 展开更多
关键词 Loading capacity flow DURATION CURVE Load DURATION CURVE EXCEEDANCE
下载PDF
Estimation of CO<sub>2</sub>Storage Capacity in the Real Sub-Seabed Sediments by Gas Hydrate
19
作者 Tao Yu Toru Sato Abuliti Abudula 《Journal of Flow Control, Measurement & Visualization》 2018年第2期82-94,共13页
Beyond conventional methods for CO2 capture and storage, a promising technology of sub-seabed CO2 storage in the form of gas hydrate has come into the limelight nowadays. In order to estimate CO2 storage capacity in t... Beyond conventional methods for CO2 capture and storage, a promising technology of sub-seabed CO2 storage in the form of gas hydrate has come into the limelight nowadays. In order to estimate CO2 storage capacity in the real sub-seabed sediments by gas hydrate, a large-scale geological model with the radius of 100 m and the thickness of 160 m was built in this study, and the processes of CO2 injection and CO2 hydrate formation in the sediments with two-phase flow were simulated numerically at three different injection rates of 10 ton/day, 50 ton/day, and 100 ton/day for an injection period of 150 days. Then, the evolutions of CO2 reaction, free CO2, and hydrate formation over time were analyzed quantitatively, and the spatial distributions of the physical properties in the sediments were presented to investigate the behaviors of CO2 hydrate formation in the sediments with two-phase flow. For CO2 storage capacity, a total amount of 15,000-ton CO2 can be stored safely in the sediments at the injection rate of 100 ton/day for 150 days, and a maximum amount of 36,500-ton CO2 could be stored in the sub-seabed sediments per year for a CO2 storage reservoir with the thickness of 100 m. For the practical scenario, an average value of 1 ton/day/m could be used to determine the actual injection rate based on the thickness of the real sub-seabed sediments. 展开更多
关键词 CO2 Capture and STORAGE Sub-Seabed CO2 STORAGE CO2 Hydrate Formation Two-Phase flow Sub-Seabed Sediments CO2 STORAGE capacity
下载PDF
Minimum Cost of Capacity Expansion for Time-Limited Transportation Problem On-Demand
20
作者 Hui Ding Zhimin Zou 《Journal of Computer and Communications》 2022年第7期53-71,共19页
The minimum cost of capacity expansion for time-limited transportation problem on-demand (MCCETLTPD) is to find such a practicable capacity expansion transportation scheme satisfying the time-limited T along with all ... The minimum cost of capacity expansion for time-limited transportation problem on-demand (MCCETLTPD) is to find such a practicable capacity expansion transportation scheme satisfying the time-limited T along with all origins’ supply and all destinations’ demands as well as the expanding cost is minimum. Actually, MCCETLTPD is a balance transportation problem and a variant problem of minimum cost maximum flow problem. In this paper, by creating a mathematical model and constructing a network with lower and upper arc capacities, MCCETLTPD is transformed into searching feasible flow in the constructed network, and consequently, an algorithm MCCETLTPD-A is developed as MCCETLTPD’s solution method basing minimum cost maximum flow algorithm. Computational study validates that the MCCETLTPD-A algorithm is an efficient approach to solving the MCCETLTPD. 展开更多
关键词 capacity Expansion Minimum Cost Maximum flow Transportation Problem Network with Lower and Upper Arc capacities
下载PDF
上一页 1 2 102 下一页 到第
使用帮助 返回顶部